The "concurrent causation" doctrine in property insurance became significant in California after the 1994 Northridge earthquake because:

• Insurers were required to offer replacement cost coverage for all earthquake losses
• Courts held that if a covered peril contributed to a loss alongside an excluded peril, the entire loss might be covered
• The California legislature mandated earthquake coverage in all HO policies after Northridge
• Courts required insurers to cover losses that were entirely caused by excluded earthquake damage